Wallpaper Calculator – How Many Rolls Do You Need?

A 12×12 ft room with 8 ft ceilings has a wall perimeter of 48 ft. Wall area = 48 × 8 = 384 sq ft, minus 2 doors (42 sq ft) and 1 window (15 sq ft) = ~327 sq ft net. At 28 sq ft per roll with 10% waste: 327 × 1.10 ÷ 28 ≈ 13 rolls. Add 1 extra for safety = 14 rolls.

Yes — always buy 1–2 extra rolls from the same batch (dye lot). Wallpaper colors vary slightly between production runs. If you need to patch damage later, a roll from a different dye lot may not match. Unused rolls can sometimes be returned; mismatched repairs cannot be undone.

US wallpaper is commonly sold as double rolls (56 sq ft per bolt) but priced by the single roll (28 sq ft). European wallpaper is sold as single rolls. When comparing prices, verify whether the price is per single or double roll to avoid ordering mistakes.

For a 24-inch repeat, add 25% to your base roll count. For example, if the plain calculation gives you 10 rolls, order 12–13 rolls. The exact waste depends on your wall height relative to the repeat size.